The present invention relates generally to the field of computed tomography imaging systems. More particularly, the invention relates to geometries and configurations for the stationary computed tomography systems in which a detector and distributed source element are fixedly positioned in an imaging system scanner.
Many applications exist for computed tomography imaging systems. Developed over recent decades, such imaging systems provide a powerful tool for imaging internal features of subjects of interest, typically presented as slices and volumes. In general, the systems consist of a source that directs radiation through the subject of interest onto a detector. Although, the source may be any type of radiation that is able to penetrate the subject of interest, special attention is given to an X-ray source in the description herein. The X-ray source and detector, in traditional systems, are mounted on a rotational gantry and spun at a relatively high rotational rate, such on the order of two rotations per second, although faster and slower speeds are also used. Measurements of the incident X-ray intensity on the detectors, are acquired at many locations during rotation and may be stored for later analysis and processing. The systems then compute useful reconstructed images by processing the acquired intensity measurements allowing determination of the location of features within the subject. While variants on this basic design have been proposed and are presently in use, current technologies exploit rotation of the source and detector, with selection of acquisition windows and special processing of the data serving to enhance clarity of the reconstructed images.
While such arrangements have proven extraordinarily useful in identifying features of interest within a subject, they are limited by the need to rotate the source and detector elements. Sources of X-rays typically have included conventional X-ray tubes which are somewhat weighty, and must be powered and cooled during the rotation. Detectors, similarly, are becoming increasingly voluminous, spanning the field of view of the imaging system at higher resolutions, and multiple rows to obtain significant amounts of data during an exam. Circuitry associated with the detectors must also be rotated to perform the data acquisition and initial processing. Engineering proficiency is required to produce a carefully balanced system with power and data transmission interconnects, along with the mechanisms to remove heat generated during operation.
There is a need, at present, for improved system designs in computed tomography. In particular, there is a significant need for a design which can lighten rotational loads, or even eliminate the need for rotation of system components all together. There is a particular need for systems that can generate high-quality images while reducing the mechanical, electrical, thermal and other problems associated with rotation of a source and a detector.